The present invention relates to an automatic metallic tube bending process and an apparatus therefor, which have a function to automatically set the bending direction, angle and position in association with the three-dimentional bending operations of a metallic tube of a relatively small diameter such as about 20 mm or less, which is frequently arranged and used as a supply passage of oil or air generally in automobiles or in a variety of machines or facilities.
In the automatic metallic tube bending process and apparatus of the above-specified kind according to the present invention, a straight tube to be worked is automatically bent suquentially in the three-dimentional bending directions in its set state, in which its one end is clamped merely by means of a chuck, in accordance with the order from the closest one of the bending positions to the chuck and positioned in advance for the bending operations by a plurality of bending units which are connected to their respective cylinder actuators and each of which is equipped with a shaping roll and a bending roll at its leading end portion arranged in a complex manner on a frame. According to these conventional process and apparatus, however, the straight tube is set by having its one end clamped so that its other end is swung in a large stroke, if it is long, when in the bending operations. At the same time, because of the complicated structure of the plural automatic bending units which are arranged in the number equal to the bending positions on the frame, the tube naturally has its outer circumference dented or damaged as a result of the abutting and rubbing contact with the bending units including their assosiative cylinder actuators. In addition, it is troublesome to load the bending units in the complicated arrangement with the straight tube and to take out the bent tube after the bending operations. Moreover, the productivity is drastically dropped by the sequential bending operations in which the tube is bent only from its one end. In connection with this background, still moreover, the straight tube to be bent is obliged to have its length limited so that the prior art can be applied only to a relatively short straight tube. Upon the bending work of many kinds of tubes each in a small number, there arises another troublesome problem that the aforementioned plural bending units have to be rearranged for each bending work.